we are using XVideo port attributes to manipulate certain image parameters (XV_BRIGHTNESS, etc), but we've noticed that calling XvSetPortAttribute upon a particular port changes the setting for all ports in that device.

We have confirmed this behavior in various systems and card models: GeForce 8600GTS, Quadro FX 880M, GeForce 220GT. Our study of other OSS NVidia card drivers (nv, nouveau) reveals that this setting is, at least, intended to affect only the port passed as parameter to XvSetPortAttribute.

Can anybody confirm this as a bug, or at least provide documentation specifying this as an expected behavior?